Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 45: Correlated Electrons: Poster Session
TT 45.66: Poster
Donnerstag, 29. März 2012, 15:00–19:00, Poster B
Quasi one-dimensional spin chain materials AM2V2O8 — •Michael Seher, Sandra Niesen, Gerhard Kolland, Oliver Heyer, Simon Scharffe, Martin Valldor, and Thomas Lorenz — II. Physikalisches Institut, Universität zu Köln
Compounds with the general formula AM2V2O8 with an alkaline-earth on the A-site and a transition-metal on the M-site show a lot of interesting properties. This class of compounds is mainly isostructural with tetragonal symmetry and provides spin chain structures. The magnetic properties are vitally influenced by the chosen transition metal with its partially filled 3d shell. Thus, these compounds are suitable to study spin systems from S=1/2 to 5/2 and spin quantum number anisotropy can be studied from Ising- to Heisenberg behavior. Here, we present a detailed study on the magnetic phase diagram of the effective S=1/2 Ising system BaCo2V2O8. Moreover, we have grown large single crystals of the nearly isotropic Heisenberg systems BaMn2V2O8 and the new compound SrMn2V2O8. At higher temperatures both compounds behave like 1D magnetic systems. But due to finite interchain couplings both systems show long-range antiferromagnetic order with TN=37 K (A= Ba) [1] and TN=43 K (A= Sr) [2].
This work is supported by the DFG through SFB 608.
[1] Z. He et al. Solid State Comm. 141 (2007) 22
[2] S.K. Niesen et al. J. Mag. Mag. Mat. 323 (2011) 2575